The transmission method disclosed in Non-Patent Literature 1 includes: (1) a step of encoding a data block with a forward error correction code (FEC code); (2) a step of mapping bits of a codeword resulting from the encoding to complex cells; and (3) a step of applying a cell interleaving to the complex cells resulting from the mapping.
The cell interleaving is processing for spreading bits that are influenced by burst errors that occur in channels (over the entire codeword), and is known as being useful as a means for improving the reception performance.